1. Field of the Invention
The invention relates to a road slope determining apparatus and method for a vehicle, which determines the slope of a road on which the vehicle is traveling.
2. Description of the Related Art
Technology is known which measures the slope of a road surface when a vehicle is traveling on a gradient, for example. Japanese Patent Publication No. 6-21641, for example, describes a control apparatus of a vehicle which, as a method for measuring the slope of a road, measures an average value of a slope measured in units of time, or more specifically, within a certain period of time, as the slope of the road.
However, in the method of measuring the slope of a road in Japanese Patent Publication No. 6-21641 described above, the slope is measured in units of time. Therefore, when the vehicle is traveling at slow or extremely slow speeds, for example, it is technically difficult to differentiate between a gradient and a rough road that is regarded as being on generally level ground, for example.